In the production of contact lenses, a polymerizable lens precursor composition can be placed on a contact lens shaped cavity of a mold assembly and can be polymerized therein to form a contact lens located in the lens shaped cavity of the mold assembly. For example, a polymerizable lens precursor composition can be exposed to ultraviolet light or heat to polymerize the composition.
After polymerizing the lens precursor composition, the mold sections are separated or demolded and the polymerized contact lens can be removed or delensed from the mold section.
Existing polymerized silicone hydrogel contact lenses are associated with ophthalmically unacceptable surface wettabilities. To make silicone hydrogel contact lenses have ophthalmically acceptable surface wettabilities, surface treatments are provided on the lenses or an interpenetrating polymeric network (IPN) of a polymeric wetting agent is included in the contact lens. Surface treatments and polymeric wetting agent IPNs can degrade over time and result in less wettable silicone hydrogel contact lenses.
There remains a need for lens precursor compositions for producing silicone hydrogel contact lenses that have one or more desirable properties, such as high oxygen permeability, water content, modulus, surface wettabilities, and the like. There also remains a need for silicone hydrogel contact lens precursor compositions that produce silicone hydrogel contact lenses that are durable during the manufacturing process to reduce incidence of damage to the contact lenses during the manufacturing process.